[Python-porting] co_names behavior change

[Tom Ekberg]

Being an old-time compiler person, I ended up using the symtable module and recursively called child.get_identifiers() to get all of the names. Attached is the diff (ignore the last 2 parts of the diff). It works with python 2.7 and 3.5.


Tom Ekberg
Senior Computer Specialist, Lab Medicine
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Work: (206) 520-4856
Email: tekberg at uw.edu


________________________________
From: Piet van Oostrum <piet-l at vanoostrum.org>
Sent: Monday, April 8, 2019 1:59 PM
To: Tom Ekberg
Cc: Python-porting at python.org
Subject: Re: [Python-porting] co_names behavior change

You can get the variable names of the embedded comprehensions with:

[lc.co_names for lc in f.__code__.co_consts if  type(lc) is types.CodeType]

where f is the function defined by the exec (f = d['f'])

But to take nested comprehensions into account you would have to write a recursive function:

from types import CodeType

def varnames(codeobj):
    names = [lc.co_names for lc in codeobj.co_consts if isinstance(lc, CodeType)]
    names += [varnames(lc) for lc in codeobj.co_consts if isinstance(lc, CodeType)]
    # flatten the list
    return [item for sublist in names for item in sublist]

print(varnames(f.__code__))

--
Piet van Oostrum <piet-l at vanoostrum.org>
WWW: http://piet.vanoostrum.org/
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